Why does one God?

[The holy Quran 17:42] Say, “If there were any other gods beside Him, as they claim, they would have tried to overthrow the Possessor of the throne.”

[17:43] Be He glorified, He is much too exalted, far above their utterances.

[21:21] Have they found gods on earth who can create?

[21:22] If there were in them (the heavens and the earth) other gods beside GOD, there would have been chaos. Glory be to GOD; the Lord with absolute authority. He is high above their claims.

[21:23] He is never to be asked about anything He does, while all others are questioned.

The holy Quran mainly gives two strong evidences as to why there is only one God.

If there is more than one god, there will be fighting among gods to occupy highest position. The Quran confirms that no such fight exists, as we could see too, so there is only one God.

If there is more than one gods, there must be chaos in everywhere in this universe. Basically we are very lucky that there is only one God. Natural laws are created and controlled by God. For example, each electron in an atom has definite quantum state which it cannot violate. If this rule were not obeyed, atom would have collapsed within a fraction of second. As atom is the building block of everything we could see or detect, there would not have any existence of matter in such situation, so no existence of human being as well. We apparently seeing, matter is inanimate but matter is more disciplined than human being in the sense that matter obeys rules of nature perfectly. This is not only a powerful evidence for the existence of a Supreme Being but it also proves that there is only one authority Who controls natural laws, hence only one God.